The heat generated in operation of an internal combustion engine of a motor vehicle is typically dissipated to the surroundings using a heat exchanger which can have an air stream flow through it. Such heat exchangers, which are commonly referred to as radiators, are designed so that even at maximum power development of the engine, also under extreme external conditions at external temperatures above approximately 40° C. and more, they provide sufficient cooling.
In the predominant number of motor vehicles, the radiator is situated in front of the internal combustion engine viewed in the travel direction, so that a part of the travel wind can be used directly as the cooling air to be supplied.
The air supply to the radiator occurs via air inlet openings of a radiator grille, which can have greatly varying embodiments as a component of the vehicle front depending on the vehicle design.
In the meantime, so-called active cooling air supply apparatuses have come into existence, which regulate the cooling air supply to the radiator on demand. Thus, for example, DE 102 28 422 A1 discloses a louver for closing openings having pivotable louver elements situated parallel to one another. Depending on the position and orientation of the louver elements, the cooling air supply to the heat exchanger, or to the internal combustion engine, can be regulated according to the cooling requirements. In addition, the flow-technology geometry of the vehicle changes with the adjustment of the louver elements. In the event of a closed radiator louver, the air resistance of the motor vehicle decreases, which is accompanied by an advantageous reduction of the fuel consumption.
An actuating drive driven by an electric motor is typically provided for the pivotable operation of individual louver elements, which is activated and regulated by the onboard electronics of the vehicle.
Because opening of the louver element or air supply lamellae is not required for cooling under normal operating conditions, the lamellae are predominantly located in their closed position, in order to reduce the air resistance of the vehicle. However, closed lamellae prevent the dissipation of heat in particular after the vehicle is shut down, so that critical overheating of the engine can occur.
Opening of ventilation openings which is solely actuated by an electric motor thus lacks in reliability. For example, if the power supply for the actuating mechanism is interrupted or other malfunctions of the vehicle electronics occur, opening of ventilation openings, which is required after the motor vehicle has been shut down and left, cannot be provided with sufficient reliability.
The present invention is thus based on at least one object of providing an improved cooling air supply apparatus for an internal combustion engine of a motor vehicle, which offers increased reliability for the opening of ventilation openings. The cooling air supply apparatus is also to be able to be actuated independently of the onboard electronics of the motor vehicle and is to be used for avoiding critical overheating of the internal combustion engine, in particular when the engine is shut down and the vehicle electronics are inactive. In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.